Aircraft bomb fuse



Nov. 14, 1950 J. c. BYRNES, JR

AIRCRAFT BOMB FUSE 2 Sheets-Sheet 1 Filed Sept. 30, 1940 INVENTOR khmea a @rnea A ORNEY Nov. 14, 1950 Filed Sept. 50, 1940 J. c. BYRNES, JR 2,529,483

AIRCRAFT BOMB FUSE 2 Sheets-Sheet 2 INVENTOR /20 BY fumes GBymeaJF' A TORNEY Patented Nov. 14, 1950 UNITED STATES PATENT OFFICE AIRCRAFT BOMB FUSE James C. Byrncs, Jr., United States Navy Application September 30, 1940, Serial No. 358,970

(Granted under the act of March 3, 1883, as amended April 30, 1928; 3'70 0. G. 757) 8 Claims.

This invention relates to nose fuses for aircraf bombs, it being an object of the invention to provide an improved fuse for aircraft bombs of the type which detonate upon impact. The improvements relate to bomb fuses of either the collapsible head or inertia element type with time delay characteristics incorporated in the detonating circuit. I

It is a further object of my invention to provide an improved aircraft bomb fuse the detonation of which will be initiated upon impact with all surfaces except liquid.

It is another object of my invention to provide a fuse the detonation of which will be initiate only upon impact with a liquid.

It is also an object of my invention to provide a bomb fuse having two detonators and two fuse trains of-entirely different characteristics. The detonation of one will be initiated upon impact with a, solid, while the detonation of the other will be initiated only upon impact with a liquid.

It is also an object of the invention to provide a bomb fuse that will, upon impact with a liquid,

operate means to prevent th detonation f the ,bomb by the action which would have been initiated if the bomb had impact against solid surface. 1

It is a, further'object of the invention to provide a bomb fuse having two fuse trains of different characteristics, the detonation of one being initiated upon impact with a solid, while'the detonation of the other is initiated only upon impact with a liquid, with a mechanism which will render the fuse train which would detonate upon impact with a solid inoperative, when the bomb impacts upon a liquid.

The above objects, as well as others which may be apparent to those skilled in the art, are attained by mechanism illustrated in the accompanying drawings, in which:

Fig. 1 is a vertical section of bomb fuse, of the collapsible head type, illustrated generally in Fig. 3.

Fig. 2 is a partial vertical section of the same bomb fuse illustrated by Fig. 1, showing the operation upon impact with a liquid.

Fig. 3 is an elevation view partly in cross-section showing the fuse attached to the body of the bomb.

' Fig. 4 is an enlarged sectional view taken on lines i4 of Fig.1, showing the shear collar and Firm shear pin. Fig. 5 is a vertical section of the bomb fuse of theinertia element type, illustrated generally by Fig. 7. Fig. 6 is a sectional View of the same fuse illustrated by Fig. 5, showing the operation upon impact with a liquid.

Fig. '7 is an elevation View partly in cross-section showing the fuse of the inertia element type attached to the bodyof the bomb.

Fig. 8 is a plan view of a section taken on line Fig. 9 is a detailed section taken on lines 9-9 1 of Fig. 1. a H

The same reference characters are used to desi natesimilar parts throughout the various views.

The bomb fuse as illustrated by Figs. 1-3, inclusive, is of the collapsible head type, and cornprises specifically a body member l, hich, in the illustrated embodiment, is threadedly secured at one end thereof to the bomb casing 2. The body member has a cavity formed in the end secured to thevbomb casing which contains the booster charge. This booster charge is enclosed by means of asuitable cover indicated generally by 2'5. Communicating with this booster charge are two ignition transmission trains 6-'E of entirely different characteristics. Train 8 is preferably a slow burning time train while train 7 may be eithera delay 01; flash transmission train, its characteristics depending upon the degree of penetration'desired. The train 5 terminates into a bore 4, which extends from the outer surface of the body member inwardly to the center portion thereof. This bore has at its inner end a slider charge 5- and a primer charge 8. In the bore there is also positioned the movable plug or slide member H which is securely held in place by means of a shear pin i2, as clearly shown by Fig. 9. I This slidable plug has a, vertical passageway 2! extending therethrough which intercom nects the delay fuse train l with its primer cap l3. The outer end of the bore is closed by means of the plug 9, which in the illustrated embodiment is screwed into the body of the fuse. This plug 9 has a transverse duct openin to the atmosphere which will allow the entrapped air to be freely exhausted upon movement of the slidable plug within the bore, as will be later described.

The fuse body I is also provided with a central cavity I4, and a, connecting duct I5 which also affords an escape to the atmosphere. This cavity It communicates with the bore 4, and primer charge 8.

In the base of the fuse body there is a movable head member 2i) which has a longitudinal stem 3 that extends into a bore I8 formed in the base of said fuse body and is retained in place spaced from the fuse body by means of a shear collar I6 formed integrally and shear pin I1, all of which are clearly shown in Figs. 1, 2 and 4.

In the base of the fuse body firing pin I9 is securely held in place by means of a shear in 2! and projects slightly from the base of the fuse body. On impact with either a liquid or solid the head 23 is retarded and the fuse body I and bomb 2 continue on by inertia, shearing the shear collar IE3 and shear pin II, closing the space (1)) between the movable head and the body, thereby driving the firing pin into the primer I3 which sets off the delay train I which in turn ignites the booster charge and detonates the explosive charge of the bomb.

In order to prevent the delay train I from detonating the bomb when same impacts on water, or similar liquid, an orifice or channel 22 is provided in the head member 20, this channel is flared as at 23 so that the fuse head need penetrate the water only a very short distance (a) which is less than the distance (12) that the head must travel before engaging the firing pin I9.

It may be noted that in the embodiment illustrated the nose of the head member is provided with a projecting portion 24, and also that the mouth of the orifice 22 is flared in this portion. of the head so that a small surface area of the bomb engages the liquid upon its initial impact. The nose of the fuse head will, therefore, penetrate the liquid a distance (a) before a sufficient surface area is encountered to offer a resistance necessary to shear the collar I6 and shear pin I'I.

When the bomb strikes the water, the slight arresting of the bombs flight on impact will shear the shear collar I6 and shear pin I1, and the head will be moved rearwardly relative to the body of the fuse. Before this action is complete, however, that is before the head has sheared its collar and shear pin or traveled a distance (1)), the head will have entered the water a distance (a), sufficient to transmit to the entering jet of water the kinetic energy of the moving bomb. The water, or other liquid,

upon which the bomb impacts will enter the flanged orifice 23 with a velocity equivalent to the velocity of the bomb. The velocity of the water in this jet or orifice is then, however, substantially increased relative to the velocity of the bomb, since the area at the mouth of the orifice 23 is greater than the area of the orifice 22, the water which is entering in the mouth is continually restricted and caused to rise in the orifice with an increasing velocity. This jet of water in the orifice impacts against the primer charge 8 with a sufiicient velocity to set off the slow burning time train, as is apparent from Fig, 2. The ignition of the primer charge also sets off the slider charge 5, shearing the slider pin I2 and moving the slider outwardly in the bore 3. The movement of this slider or movable plug in the bore cuts the delay train I before the movable head 20 can travel the distance (b) to strike the firing pin I9, thereby preventing 4 the explosive charge of the bomb from being set off by the action initiated by the firing pin I9. The duct II formed in the plug 9 allows the air to escape on the movement of the slider member. It is to be noted also that the rear of the slider member has a cutaway portion which will allow the gases formed up by ignition of the firing cap I3 to escape into the cavity I4 and out the duct I5 to the atmosphere. The duct 26 formed in the body to facilitate construction of the slow burning powder train 6 is provided with a suitable plug (not shown) in the finished bomb fuse.

It is obvious, therefore, from the above description that the detonation of the bomb may be initiated in all impacts except those on water, when another train 3 having entirely different characteristics may be used.

The modification illustrated by Figs. 5, 6 and '7, shows my improvement as applied to a bomb fuse of the inertia element type. In the modification herein illustrated the head member 20 is rigidly secured to the body member I. This head member is provided with an orifice 22' similar to that indicated in Figs. 1 and 2, with flared opening 23 formed in the projecting nose portion 24 of the rigid head.

The fuse body of this modification is also provided with a cavity formed in the end thereof containing the booster charge, which communicates with the two transmission fuse trains 6 and I. A bore 4 is formed in the body and extends from the outer surface inwardly to the central portion thereof, where it communicates with a centrally formed cavity I4 and connecting orifice I5, as clearly shown in Fig. 8. The bore 4 contains the primer 8' and slider charge 9, as well as the movable plug or slider member ID which is securely held in the position indicated in Fig. 5 by means of the shear pin I2. This slider member has a vertical passageway 2'! which forms a continuation of the delay or tetryl lead in train I, and connects this delay train with its detonating charge 3E), and constitutes a movable cut-off for this transmission train, as is apparent from the description set out above concerning Figs. 1 to 3, inclusive.

The body member of this modification is also provided with a cavity 28 containing the detonating charge 30, inertia element 29, and primer 3|. train is held in place by means of the sleeve members 32 and 33.

The inertia element indicated generally at 29 consists specifically of a container member 34 having a centrally disposed shear collar 35 formed integrally therewith. The edges of the container are crimped over a closing disc 36 to complete the enclosure. The sleeve members 32 and 33 engage the shear collar to hold the inertia element securely in place and out of engagement with the anvil member 31.

On impact with either a solid or liquid the head 20 is retarded; however, the inertia element 29 will continue on by its own inertia shearing the collar 35 and impacting with considerable velocity against the anvil 31. This impact will set off the primer 3 I, the charge 30, and the delay train I, which through the booster will detonate the explosive charge of the bomb.

The detonating charge 30 for the delayof the bomb and shear the collar 35 on the inertia firing element 29. The impact of the bomb on the liquid will cause the liquid to enter the flanged orifice 23, with a velocity equivalent to the velocity of the bomb. The velocity of the Water in this jet or orifice is then, however, substantially increased relative to the velocity of the bomb by the flared formation at its mouth, so that the entering jet will impact against the firing pin 8', setting off the slider charge and the timed transmission train 6'.

The slidable member ID is moved outwardly in the bore by the explosion of the slider charge, thereby cutting the delay time train 7' in the same manner as described in the modification illustrated by Figs. 1 to 3, inclusive.

There is an obvious advantage in the bomb fuse of my invention in that the detonation of the bomb may occur after a selected time interval, upon impact with water, or similar liquid and after another selected time interval from the instant of impact on solids.

Other modifications and changes in the number and arrangement of the parts may be made by those skilled in the art without departing from the nature of the invention, within the scope of What is hereinafter claimed.

The invention described hereinma be manufactured and/or used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

Having thus set forth and disclosed the nature of this invention, what is claimed is:

1. In an aircraft bomb fuse, the combination of a fuse body having a booster charge, a pair of fuse transmission means connected to said booster charge, a primer for setting off one of said fuse transmission means on impact with a solid, a primer for also setting off the other said fuse transmission means on impact with a liquid means for interrupting the first memtioned fuse transmission means and means operative upon the ignition of the second mentioned fuse transmission means to render operative said interrupting means.

2. In an aircraft bomb fuse, the combination of a fuse body having a single booster charge fast and slow burning fuse transmission trains connected therewith, means for setting off the fast burning transmission train on impact, means for also setting off the slow burning transmission train when such impact iswith a liquid, and means for rendering the fast burning fuse means inoperative upon the setting off of said slow burning fuse means.

3. In an aircraft bomb fuse for attachment to the nose of a bomb, a body member having plural fuse transmission means, a movable head member having a projecting nose portion extending therefrom, and a vertical orifice extending therethrou gh, means effective by substantial movement of said head upon impact for igniting one of said transmission trains, the nose and orifice being constructed and arranged to permit the head to penetrate a liquid upon impact therewith a certain distance, without offering a surface resistance thereto sufficient to effect any substantial movement of the head, means responv sive to the flow of liquid through said orifice upon such penetration of said head into said liquid for igniting a second transmission train in advance of movement of said head and resultant ignition of said first transmission train, and

means responsive to the ignition of said second transmission train.

4. In a combined solid and liquid contact fuse assembly for attachment to the nose portion of a shell the combination comprising a fuse body, a booster charge chambertherein, a pair of separate fuse trains connected to said booster chamber, a detonator for each of said trains for-ignition thereof, means for firing one of said detonators upon impact, means for also firing the other said detonator when such impact is with aailiquid, and means operative upon the firing of the liquid impact detonator andignition' of the fuse train connected thereto to close 01f and thereby render inoperative the other said fuse train.

5. In a fuse, the combination of a fuse body having a booster charge, a pair of fuse transmission trains connected thereto, the first of said trains having a time characteristic shorter than that of the second, means for initiating ignition of the first train upon impact, means for also initiating ignition of the second train When such impact is with a liquid and in advance of ignition of said first train, and means for closing off said first train upon ignition of the second train.

6. A fuse for attachment to the nose of an aircraft bomb comprising a body member having a chamber therein containing a booster charge, a head member having an axial orifice therethrough, a first means for setting off the booster charge comprising a primer, a fuse train connecting said primer and booster charge and inertia operated means for detonating the primer, means for also setting off the booster charge upon impact with a liquid comprising a second primer, a second fuse train connecting said second primer and booster charge and means operable by impact of the liquid passed through said orifice for detonating said second primer, said head and orifice being constructed and arranged so that upon impact with a liquid said second primer will be detonated in advance of said first primer, and means responsive to the detonation of said second primer to interrupt said first fuse train.

'7. In a bomb the combination including a main explosive, a booster, charge therefor, a pair of fuse transmission trains leading to said booster charge, a primer for each of said trains, inertia operated means for detonating one of said primers upon impact of said bomb, means operable also upon impact of said bomb with a liquid to detonate the other primer in advance of the detonation of first said primer, and means responsive to the detonation of second said primer to place a barrier across the path of the fuse transmission train associated with first said primer.

8. A fuse for attachment to the nose portion of a bomb comprising a body member, a chamber therein containing a booster charge, fast and slow burning fuse transmission trains connected to said booster charge chamber, a primer for ignition of each of said fuse trains, a head member for said fuse provided with an impact surface of substantially frusto-conical contour and containing an axially bored orifice terminating closely adjacent the primer associated with the slow burning fuse train, inertia operated means incorporated in said body for detonating the primer associated with the fast burning fuse train upon impact of said head member, means operable in advance of the operation of said inertia operated means for also detonating the primer associated with the slow burning fuse upon the impact of said head member with a liquid comprising the impact by a jet of said liquid passed through said orifice against said primer, and means responsive to the detonation of last said primer for closing ofi said fast fuse train.

JAMES C. BYRNES, JR.

REFERENCES CITED The following references are of record in the file of this patent:

Number 8 UNITED STATES PATENTS Name Date Merriam July 1, 1890 Isham Apr. 11, 1916 McCombs Jan. 7, 1919 Nichols Feb. 27, 1923 Ogden Dec. 4, 1928 Brayton Mar. 25, 1930 Eichschmidt May 6, 1941 FOREIGN PATENTS Country Date Number Great Britain Jan. 18, 1934 

